Who said anything about trading. I said just buy BTC for $560. When you buy a miner you're doing the same thing in a roundabout way with risk/benefit of variable ROI.
Bitcoin is a bidirectional digital currency. The reason it is catagorised as this, is because BTCs design allows users to buy and sell this virtual currency on exchanges, so cash is traded for virtual currency, and currency can be exchanged for cash - this activity is called trading.
It also allows a user to directly purchase goods and services whether virtual or real. When you buy a miner you are buying physical goods. When you buy BTC with fiat, that is participating in trading whether you want to call it something else or not.